Blind rivets which are made from a hollow metal rivet body comprised of a sleeve and a rivet head at one end of a sleeve and a metal mandrel, the shaft of which extends through the through-hole of a rivet body, are well known. Blind rivets have the advantage that several mounted components can be joined by an operation on one side only.
When fastening mounted components with blind rivets, a tool for fastening blind rivets is used. The tool for fastening blind rivets is provided with a nose piece which is placed at the front end of the nose housing and which has an aperture for inserting the mandrel of the blind rivet; a jaw guide which has an inner circumferential surface which is formed so that the inner diameter thereof decreases towards the front end, and which is placed so as to be moveable forward and back in the nose housing and is contiguous with the back of the nose piece; jaws which have an outer circumferential surface which contacts slidably with the inner circumferential surface of the jaw guide, and which are placed within the jaw guide so as to grip the mandrel of the blind rivet; and a jaw pusher which pushes the jaws forward and which is placed inside the nose housing and is contiguous with the back of the jaws.
When fastening a blind rivet to a mounted component using a blind rivet fastening tool, the mandrel of the blind rivet is inserted into the aperture of the nose piece of the fastening tool; it is attached in this state, with the rivet body projecting from the nose piece. In this state, the fastening tool is positioned so that the rivet body is inserted into the mounting hole of the mounted component. Next, the fastening tool is put into operation and pulls the mandrel hard enough to break it, and the blind rivet is fastened to the mounted component by deforming the sleeve of the rivet body by expanding the diameter thereof. The broken mandrels are ejected to the back of the fastening tool and collected in a receptacle. Following this, the jaw guide returns to its starting position for attaching the next blind rivet.
There are many types of blind rivets. Blind rivets are known which fasten by pulling out the mandrel, and after expanding the diameter of one end of the sleeve of the rivet body, the rivet head is squeezed in from the outer circumference by the nose piece of the fastening tool, and the inner circumference of the rivet head engages with the shaft of the mandrel. The fastening tool for fastening this sort of blind rivet cannot increase the outer diameter of the rivet head, because the rivet head is squeezed in by means of the nose piece. For this reason, this is often used with a washer in combination. Also, because the rivet head is gripped in the aperture of the nose piece after fastening, a mechanism for pushing it out of the nose piece is necessary.
Patent Reference 1 discloses a two-component snap fastener tool which is comprised of a tubular collar and a pin component having an enlarged projecting head and a long, thin shaft, and a method of fastening with this snap fastener tool. In the two-component snap fastener of Patent Reference 1, the long, thin shaft of the pin component extends through the aperture of the work piece, and the collar is swaged into a snap retaining groove of the pin component. The shaft of the pin component shears off at a breaking neck portion groove and is fastened. The tool has a rim portion which engages in a tensioning groove of the pin, inside a tubular collet assembly which is supported so as to be capable of sliding in an anvil housing.
Patent Reference 1 discloses that a collar release component of the tool releases the collar which has been made by a swaging step. However, when the two-component snap fastener is set in the tool, it is necessary to open the rim portion of the tool so that it grips the tensioning groove.
Patent Reference 2 discloses a tool for swage-setting a fastener with a two-component structure which is comprised of a pin which passes through the concentric holes of a two-sheeted plate and a sleeve which fits together with the outside of the pin. This tool attaches an outside anvil body which engages with the guard portion of the sleeve of the fastener to a gun body which has a mechanism for gripping and pulling the pin of the fastener. The anvil at the tip of the anvil body has a center hole and carries out the swaging step.
Patent Reference 2 discloses that the pin component is ejected from a center aperture by means of an ejector component which is moveable within the housing. However, when the fastener is set on the tool, the chuck of the tool is made to contact a cap of the back surface, and it is necessary to open the chuck to do the setting.
In Patent References 1 and 2, part of the rivet body is deformed by enlarging the diameter thereof, and the rivet is fastened by deforming the rivet head by squeezing it in. Because the rivet head is squeezed in by the nose piece, it has a mechanism for kicking out the rivet head from the nose piece after fastening.
In existing tools for fastening blind rivets, a jaw guide is placed in the tip of the inside of a nose piece, and jaws are placed on an inner circumference which narrows towards the front end of the jaw guide. The jaws of the fastening tool are closed in the starting position because the jaws are pushed forward. For this reason, it is necessary to set the rivets by opening the jaws of the tool for fastening blind rivets.
If the jaws are open at the starting position, setting the rivets in such a fashion is possible and convenient. For this reason, a tool for fastening blind rivets is sought in which the jaws are open at the starting position.